Influence of Separation on Flexural Performance of Reinforced Concrete Beams Reinforced by Carbon Fiber Reinforced Polymer Sheets

Abstract

In this study, it was investigated experimentally that flexural performance of RC beam reinforced by using CFRP sheet which has separation of CFRP sheet caused by secular degradation or substandard execution. The specimens were RC beams with several conditions of CFRP sheet separation at bending span and strengthening methods by CFRP sheet at anchorage. The bending test of RC beams and the adhesion test of CFRP sheet were performed. The strength of RC beam was improved by CFRP sheet strengthening in comparison with conventional RC beam and estimated by existing methods. The adhesive strength between CFRP sheet and concrete at the anchorage zone were 1.12-2.53 MPa, which were the same value as tensile concrete strength and enough. When separation occurred between CFRP sheet and concrete at bending span of RC beams, the flexural behavior of RC beams, especially about strain or stress distribution of CFRP sheet, was influenced by methods of anchorage and characteristic property of concrete at the anchorage zone. And it was confirmed no effects of preventing the progress of crack in this case. We could say that it was necessary to pay attention in case of using CFRP sheet for repairing RC member deterioration by rebar corrosion or crack.